The invention relates to an oxygen separation device employing an oxygen transport membrane for removing oxygen from a first supplied oxygen-containing gas and feeding it to a second supplied gas to be enriched with oxygen. Such oxygen separation devices can be used, particularly in power plants, for providing the oxygen required for combustion, and to thereby reduce emissions, especially CO2 emissions during the combustion of fossil fuels, by using molecular oxygen, instead of air, for the combustion.
An oxygen separation device usually comprises a housing in which a membrane body separates a first chamber from a second chamber. The membrane body comprises said oxygen transport membrane that has a retention side and a permeation side and is designed so that it transports oxygen from the retention side to the permeation side. The housing comprises a first inlet that communicates with the first chamber and is used to introduce an oxygen-containing gas, for example ambient air, into the first chamber. The housing furthermore comprises a second inlet that communicates with the second chamber and is used to introduce a gas to be enriched with oxygen, for example recycled combustion waste gas, into the second chamber.
The membrane body is usually arranged inside the housing in such a way that the retention side of the oxygen transport membrane forms a wall section of the first chamber, and the permeation side of the oxygen transport membrane forms a wall section of the second chamber. In this manner, the oxygen transport membrane is able to remove oxygen from the oxygen-containing gas in the first chamber during operation of the oxygen transport membrane, and feed it into the gas to be enriched with oxygen in the second chamber. Accordingly, a gas with reduced oxygen content is produced in the first chamber, while an oxygen-enriched gas is formed in the second chamber.
The housing also is provided with a first outlet that communicates with the first chamber and is used to discharge the oxygen-reduced gas from the first chamber. Analogously, the housing is also provided with a second outlet that communicated with the second chamber and is used to discharge the oxygen-enriched gas from the second chamber.
To ensure proper function of the oxygen separation device, it is important to avoid leaks between the first chamber and the second chamber. The positioning and sealing of the membrane body in the housing is therefore of critical importance. A sealed positioning of the membrane body in the housing is made difficult by the fact that thermal expansions during the operation of the device are inevitable, so that the respectively used bearings and seals must be able to compensate the thermal expansion effects. At the same time, tensions in the material of the membrane body must be prevented because the oxygen transport membrane is usually produced of a ceramic material that can be easily damaged by material tensions.
The invention means to remedy this. The invention has the objective of disclosing an embodiment of an oxygen separation device in which a sealed positioning of the membrane body in the housing is simplified, and in which the joint zone with the housing, in relation to the membrane surface, is kept very small.
In a first exemplary embodiment, this objective is realized with an oxygen separation device comprising a membrane body and a housing, in which the membrane body separates a first chamber from a second chamber. The housing comprises a first inlet that communicates with the first chamber and is used to introduce an oxygen-containing gas and a second inlet that communicates with the second chamber and is used to introduce a gas to be enriched with oxygen. The membrane body comprises an oxygen transport membrane that has a retention side and a permeation side and is designed so that it transports oxygen from the retention side to the permeation side. The membrane body is arranged inside the housing in such a way that the retention side of the oxygen transport membrane communicates with the first chamber, and the permeation side of the oxygen transport membrane communicates with the second chamber. The oxygen transport membrane removes oxygen from the introduced oxygen-containing gas and feeds this oxygen into the introduced gas to be enriched with oxygen, so that in the first chamber an oxygen-reduced gas and in the second chamber an oxygen-enriched gas are formed. The housing comprises a first outlet that communicates with the first chamber and is used to discharge the oxygen-reduced gas and a second outlet that communicates with the second chamber and is used to discharge the oxygen-enriched gas. The membrane body is provided with several juxtaposed channels that are divided into first channels and second channels, the channels arranged in the housing in such a way that a first end of each channel on one side of the membrane body is exposed to the first chamber, while a second end of each channel on the other side of the membrane body is exposed to the second chamber. In all first channels, the first end is constructed open, and the second end is constructed closed. In all second channels, the first end is constructed closed, and the second end is constructed open. The membrane body is constructed so that adjoining channels have common walls and the walls of the channels are formed by the oxygen transport membrane. The oxygen transport membrane is positioned so that an inside of the first channels is formed by the retention side of the oxygen transport membrane, and an inside of the second channels is formed by the permeation side of the oxygen transport membrane. The membrane body is held in a gas-tight manner on an outside between the ends of the channels by way of holding means at the housing.
In a second exemplary embodiment, the oxygen separation device has a housing comprising a first inlet, a second inlet, a first outlet, and a second outlet, a membrane body comprising an oxygen transport membrane and a plurality of juxtaposed channels and separating the housing into a first chamber and second chamber, the oxygen transport membrane having a retention side and a permeation side and designed to transport oxygen from the retention side to the permeation side, and the plurality of juxtaposed channels divided into first channels and second channels and arranged in the housing such that a first end of each channel on one side of the membrane body is exposed to the first chamber and a second end of each channel on another side of the membrane body is exposed to the second chamber, and means for holding the membrane body in a gas-tight manner at an outside between the ends of the channels by way of holding means. The retention side of the oxygen transport membrane communicates with the first chamber and the permeation side of the oxygen transport membrane communicates with the second chamber. The first inlet communicates with the first chamber and is used to introduce an oxygen-containing gas and the second inlet communicates with the second chamber and is used to introduce a gas to be enriched with oxygen. The oxygen transport membrane removes oxygen from the introduced oxygen-containing gas and feeds the oxygen into the introduced gas to be enriched with oxygen, so that in the first chamber an oxygen-reduced gas and in the second chamber an oxygen-enriched gas are formed. The first outlet communicates with the first chamber and is used to discharge the oxygen-reduced gas and the second outlet communicates with the second chamber and is used to discharge the oxygen-enriched gas. In all first channels, the first end is constructed open and the second end is constructed closed and in all second channels, the first end is constructed closed, and the second end is constructed open. The membrane body is constructed so that adjoining first and second channels have a common wall, the walls of the channels formed by the oxygen transport membrane. The oxygen transport membrane is positioned so that an inside of the first channels is formed by the retention side of the oxygen transport membrane, and an inside of the second channels is formed by the permeation side of the oxygen transport membrane.